// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_API_H_
#define V8_API_H_

#include "include/v8-testing.h"
#include "src/contexts.h"
#include "src/detachable-vector.h"
#include "src/heap/factory.h"
#include "src/isolate.h"
#include "src/objects.h"
#include "src/objects/bigint.h"
#include "src/objects/js-collection.h"
#include "src/objects/js-generator.h"
#include "src/objects/js-promise.h"
#include "src/objects/js-proxy.h"
#include "src/objects/module.h"
#include "src/objects/shared-function-info.h"

#include "src/objects/templates.h"

namespace v8 {

namespace internal {
    class JSArrayBufferView;
} // namespace internal

namespace debug {
    class GeneratorObject;
    class Script;
    class WeakMap;
} // namespace debug

// Constants used in the implementation of the API.  The most natural thing
// would usually be to place these with the classes that use them, but
// we want to keep them out of v8.h because it is an externally
// visible file.
class Consts {
public:
    enum TemplateType {
        FUNCTION_TEMPLATE = 0,
        OBJECT_TEMPLATE = 1
    };
};

template <typename T>
inline T ToCData(v8::internal::Object obj);

template <>
inline v8::internal::Address ToCData(v8::internal::Object obj);

template <typename T>
inline v8::internal::Handle<v8::internal::Object> FromCData(
    v8::internal::Isolate* isolate, T obj);

template <>
inline v8::internal::Handle<v8::internal::Object> FromCData(
    v8::internal::Isolate* isolate, v8::internal::Address obj);

class ApiFunction {
public:
    explicit ApiFunction(v8::internal::Address addr)
        : addr_(addr)
    {
    }
    v8::internal::Address address() { return addr_; }

private:
    v8::internal::Address addr_;
};

class RegisteredExtension {
public:
    static void Register(std::unique_ptr<Extension>);
    static void UnregisterAll();
    Extension* extension() const { return extension_.get(); }
    RegisteredExtension* next() const { return next_; }
    static RegisteredExtension* first_extension() { return first_extension_; }

private:
    explicit RegisteredExtension(Extension*);
    explicit RegisteredExtension(std::unique_ptr<Extension>);
    std::unique_ptr<Extension> extension_;
    RegisteredExtension* next_ = nullptr;
    static RegisteredExtension* first_extension_;
};

#define OPEN_HANDLE_LIST(V)                      \
    V(Template, TemplateInfo)                    \
    V(FunctionTemplate, FunctionTemplateInfo)    \
    V(ObjectTemplate, ObjectTemplateInfo)        \
    V(Signature, FunctionTemplateInfo)           \
    V(AccessorSignature, FunctionTemplateInfo)   \
    V(Data, Object)                              \
    V(RegExp, JSRegExp)                          \
    V(Object, JSReceiver)                        \
    V(Array, JSArray)                            \
    V(Map, JSMap)                                \
    V(Set, JSSet)                                \
    V(ArrayBuffer, JSArrayBuffer)                \
    V(ArrayBufferView, JSArrayBufferView)        \
    V(TypedArray, JSTypedArray)                  \
    V(Uint8Array, JSTypedArray)                  \
    V(Uint8ClampedArray, JSTypedArray)           \
    V(Int8Array, JSTypedArray)                   \
    V(Uint16Array, JSTypedArray)                 \
    V(Int16Array, JSTypedArray)                  \
    V(Uint32Array, JSTypedArray)                 \
    V(Int32Array, JSTypedArray)                  \
    V(Float32Array, JSTypedArray)                \
    V(Float64Array, JSTypedArray)                \
    V(DataView, JSDataView)                      \
    V(SharedArrayBuffer, JSArrayBuffer)          \
    V(Name, Name)                                \
    V(String, String)                            \
    V(Symbol, Symbol)                            \
    V(Script, JSFunction)                        \
    V(UnboundModuleScript, SharedFunctionInfo)   \
    V(UnboundScript, SharedFunctionInfo)         \
    V(Module, Module)                            \
    V(Function, JSReceiver)                      \
    V(Message, JSMessageObject)                  \
    V(Context, Context)                          \
    V(External, Object)                          \
    V(StackTrace, FixedArray)                    \
    V(StackFrame, StackTraceFrame)               \
    V(Proxy, JSProxy)                            \
    V(debug::GeneratorObject, JSGeneratorObject) \
    V(debug::Script, Script)                     \
    V(debug::WeakMap, JSWeakMap)                 \
    V(Promise, JSPromise)                        \
    V(Primitive, Object)                         \
    V(PrimitiveArray, FixedArray)                \
    V(BigInt, BigInt)                            \
    V(ScriptOrModule, Script)

class Utils {
public:
    static inline bool ApiCheck(bool condition,
        const char* location,
        const char* message)
    {
        if (!condition)
            Utils::ReportApiFailure(location, message);
        return condition;
    }
    static void ReportOOMFailure(v8::internal::Isolate* isolate,
        const char* location, bool is_heap_oom);

    static inline Local<Context> ToLocal(
        v8::internal::Handle<v8::internal::Context> obj);
    static inline Local<Value> ToLocal(
        v8::internal::Handle<v8::internal::Object> obj);
    static inline Local<Module> ToLocal(
        v8::internal::Handle<v8::internal::Module> obj);
    static inline Local<Name> ToLocal(
        v8::internal::Handle<v8::internal::Name> obj);
    static inline Local<String> ToLocal(
        v8::internal::Handle<v8::internal::String> obj);
    static inline Local<Symbol> ToLocal(
        v8::internal::Handle<v8::internal::Symbol> obj);
    static inline Local<RegExp> ToLocal(
        v8::internal::Handle<v8::internal::JSRegExp> obj);
    static inline Local<Object> ToLocal(
        v8::internal::Handle<v8::internal::JSReceiver> obj);
    static inline Local<Object> ToLocal(
        v8::internal::Handle<v8::internal::JSObject> obj);
    static inline Local<Function> ToLocal(
        v8::internal::Handle<v8::internal::JSFunction> obj);
    static inline Local<Array> ToLocal(
        v8::internal::Handle<v8::internal::JSArray> obj);
    static inline Local<Map> ToLocal(
        v8::internal::Handle<v8::internal::JSMap> obj);
    static inline Local<Set> ToLocal(
        v8::internal::Handle<v8::internal::JSSet> obj);
    static inline Local<Proxy> ToLocal(
        v8::internal::Handle<v8::internal::JSProxy> obj);
    static inline Local<ArrayBuffer> ToLocal(
        v8::internal::Handle<v8::internal::JSArrayBuffer> obj);
    static inline Local<ArrayBufferView> ToLocal(
        v8::internal::Handle<v8::internal::JSArrayBufferView> obj);
    static inline Local<DataView> ToLocal(
        v8::internal::Handle<v8::internal::JSDataView> obj);
    static inline Local<TypedArray> ToLocal(
        v8::internal::Handle<v8::internal::JSTypedArray> obj);
    static inline Local<Uint8Array> ToLocalUint8Array(
        v8::internal::Handle<v8::internal::JSTypedArray> obj);
    static inline Local<Uint8ClampedArray> ToLocalUint8ClampedArray(
        v8::internal::Handle<v8::internal::JSTypedArray> obj);
    static inline Local<Int8Array> ToLocalInt8Array(
        v8::internal::Handle<v8::internal::JSTypedArray> obj);
    static inline Local<Uint16Array> ToLocalUint16Array(
        v8::internal::Handle<v8::internal::JSTypedArray> obj);
    static inline Local<Int16Array> ToLocalInt16Array(
        v8::internal::Handle<v8::internal::JSTypedArray> obj);
    static inline Local<Uint32Array> ToLocalUint32Array(
        v8::internal::Handle<v8::internal::JSTypedArray> obj);
    static inline Local<Int32Array> ToLocalInt32Array(
        v8::internal::Handle<v8::internal::JSTypedArray> obj);
    static inline Local<Float32Array> ToLocalFloat32Array(
        v8::internal::Handle<v8::internal::JSTypedArray> obj);
    static inline Local<Float64Array> ToLocalFloat64Array(
        v8::internal::Handle<v8::internal::JSTypedArray> obj);
    static inline Local<BigInt64Array> ToLocalBigInt64Array(
        v8::internal::Handle<v8::internal::JSTypedArray> obj);
    static inline Local<BigUint64Array> ToLocalBigUint64Array(
        v8::internal::Handle<v8::internal::JSTypedArray> obj);

    static inline Local<SharedArrayBuffer> ToLocalShared(
        v8::internal::Handle<v8::internal::JSArrayBuffer> obj);

    static inline Local<Message> MessageToLocal(
        v8::internal::Handle<v8::internal::Object> obj);
    static inline Local<Promise> PromiseToLocal(
        v8::internal::Handle<v8::internal::JSObject> obj);
    static inline Local<StackTrace> StackTraceToLocal(
        v8::internal::Handle<v8::internal::FixedArray> obj);
    static inline Local<StackFrame> StackFrameToLocal(
        v8::internal::Handle<v8::internal::StackTraceFrame> obj);
    static inline Local<Number> NumberToLocal(
        v8::internal::Handle<v8::internal::Object> obj);
    static inline Local<Integer> IntegerToLocal(
        v8::internal::Handle<v8::internal::Object> obj);
    static inline Local<Uint32> Uint32ToLocal(
        v8::internal::Handle<v8::internal::Object> obj);
    static inline Local<BigInt> ToLocal(
        v8::internal::Handle<v8::internal::BigInt> obj);
    static inline Local<FunctionTemplate> ToLocal(
        v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
    static inline Local<ObjectTemplate> ToLocal(
        v8::internal::Handle<v8::internal::ObjectTemplateInfo> obj);
    static inline Local<Signature> SignatureToLocal(
        v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
    static inline Local<AccessorSignature> AccessorSignatureToLocal(
        v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
    static inline Local<External> ExternalToLocal(
        v8::internal::Handle<v8::internal::JSObject> obj);
    static inline Local<Function> CallableToLocal(
        v8::internal::Handle<v8::internal::JSReceiver> obj);
    static inline Local<Primitive> ToLocalPrimitive(
        v8::internal::Handle<v8::internal::Object> obj);
    static inline Local<PrimitiveArray> ToLocal(
        v8::internal::Handle<v8::internal::FixedArray> obj);
    static inline Local<ScriptOrModule> ScriptOrModuleToLocal(
        v8::internal::Handle<v8::internal::Script> obj);

#define DECLARE_OPEN_HANDLE(From, To)                                \
    static inline v8::internal::Handle<v8::internal::To> OpenHandle( \
        const From* that, bool allow_empty_handle = false);

    OPEN_HANDLE_LIST(DECLARE_OPEN_HANDLE)

#undef DECLARE_OPEN_HANDLE

    template <class From, class To>
    static inline Local<To> Convert(v8::internal::Handle<From> obj);

    template <class T>
    static inline v8::internal::Handle<v8::internal::Object> OpenPersistent(
        const v8::Persistent<T>& persistent)
    {
        return v8::internal::Handle<v8::internal::Object>(
            reinterpret_cast<v8::internal::Address*>(persistent.val_));
    }

    template <class T>
    static inline v8::internal::Handle<v8::internal::Object> OpenPersistent(
        v8::Persistent<T>* persistent)
    {
        return OpenPersistent(*persistent);
    }

    template <class From, class To>
    static inline v8::internal::Handle<To> OpenHandle(v8::Local<From> handle)
    {
        return OpenHandle(*handle);
    }

    static inline CompiledWasmModule Convert(
        std::shared_ptr<i::wasm::NativeModule> native_module)
    {
        return CompiledWasmModule { std::move(native_module) };
    }

private:
    static void ReportApiFailure(const char* location, const char* message);
};

template <class T>
inline T* ToApi(v8::internal::Handle<v8::internal::Object> obj)
{
    return reinterpret_cast<T*>(obj.location());
}

template <class T>
inline v8::Local<T> ToApiHandle(
    v8::internal::Handle<v8::internal::Object> obj)
{
    return Utils::Convert<v8::internal::Object, T>(obj);
}

template <class T>
inline bool ToLocal(v8::internal::MaybeHandle<v8::internal::Object> maybe,
    Local<T>* local)
{
    v8::internal::Handle<v8::internal::Object> handle;
    if (maybe.ToHandle(&handle)) {
        *local = Utils::Convert<v8::internal::Object, T>(handle);
        return true;
    }
    return false;
}

namespace internal {

    class V8_EXPORT_PRIVATE DeferredHandles {
    public:
        ~DeferredHandles();

    private:
        DeferredHandles(Address* first_block_limit, Isolate* isolate)
            : next_(nullptr)
            , previous_(nullptr)
            , first_block_limit_(first_block_limit)
            , isolate_(isolate)
        {
            isolate->LinkDeferredHandles(this);
        }

        void Iterate(RootVisitor* v);

        std::vector<Address*> blocks_;
        DeferredHandles* next_;
        DeferredHandles* previous_;
        Address* first_block_limit_;
        Isolate* isolate_;

        friend class HandleScopeImplementer;
        friend class Isolate;
    };

    // This class is here in order to be able to declare it a friend of
    // HandleScope.  Moving these methods to be members of HandleScope would be
    // neat in some ways, but it would expose internal implementation details in
    // our public header file, which is undesirable.
    //
    // An isolate has a single instance of this class to hold the current thread's
    // data. In multithreaded V8 programs this data is copied in and out of storage
    // so that the currently executing thread always has its own copy of this
    // data.
    class HandleScopeImplementer {
    public:
        class EnteredContextRewindScope {
        public:
            explicit EnteredContextRewindScope(HandleScopeImplementer* hsi)
                : hsi_(hsi)
                , saved_entered_context_count_(hsi->EnteredContextCount())
            {
            }

            ~EnteredContextRewindScope()
            {
                DCHECK_LE(saved_entered_context_count_, hsi_->EnteredContextCount());
                while (saved_entered_context_count_ < hsi_->EnteredContextCount())
                    hsi_->LeaveContext();
            }

        private:
            HandleScopeImplementer* hsi_;
            size_t saved_entered_context_count_;
        };

        explicit HandleScopeImplementer(Isolate* isolate)
            : isolate_(isolate)
            , spare_(nullptr)
            , call_depth_(0)
            , last_handle_before_deferred_block_(nullptr)
        {
        }

        ~HandleScopeImplementer()
        {
            DeleteArray(spare_);
        }

        // Threading support for handle data.
        static int ArchiveSpacePerThread();
        char* RestoreThread(char* from);
        char* ArchiveThread(char* to);
        void FreeThreadResources();

        // Garbage collection support.
        V8_EXPORT_PRIVATE void Iterate(v8::internal::RootVisitor* v);
        V8_EXPORT_PRIVATE static char* Iterate(v8::internal::RootVisitor* v,
            char* data);

        inline internal::Address* GetSpareOrNewBlock();
        inline void DeleteExtensions(internal::Address* prev_limit);

        // Call depth represents nested v8 api calls.
        inline void IncrementCallDepth() { call_depth_++; }
        inline void DecrementCallDepth() { call_depth_--; }
        inline bool CallDepthIsZero() { return call_depth_ == 0; }

        inline void EnterContext(Context context);
        inline void LeaveContext();
        inline bool LastEnteredContextWas(Context context);
        inline size_t EnteredContextCount() const { return entered_contexts_.size(); }

        inline void EnterMicrotaskContext(Context context);

        // Returns the last entered context or an empty handle if no
        // contexts have been entered.
        inline Handle<Context> LastEnteredContext();
        inline Handle<Context> LastEnteredOrMicrotaskContext();

        inline void SaveContext(Context context);
        inline Context RestoreContext();
        inline bool HasSavedContexts();

        inline DetachableVector<Address*>* blocks() { return &blocks_; }
        Isolate* isolate() const { return isolate_; }

        void ReturnBlock(Address* block)
        {
            DCHECK_NOT_NULL(block);
            if (spare_ != nullptr)
                DeleteArray(spare_);
            spare_ = block;
        }

        static const size_t kEnteredContextsOffset;
        static const size_t kIsMicrotaskContextOffset;

    private:
        void ResetAfterArchive()
        {
            blocks_.detach();
            entered_contexts_.detach();
            is_microtask_context_.detach();
            saved_contexts_.detach();
            spare_ = nullptr;
            last_handle_before_deferred_block_ = nullptr;
            call_depth_ = 0;
        }

        void Free()
        {
            DCHECK(blocks_.empty());
            DCHECK(entered_contexts_.empty());
            DCHECK(is_microtask_context_.empty());
            DCHECK(saved_contexts_.empty());

            blocks_.free();
            entered_contexts_.free();
            is_microtask_context_.free();
            saved_contexts_.free();
            if (spare_ != nullptr) {
                DeleteArray(spare_);
                spare_ = nullptr;
            }
            DCHECK_EQ(call_depth_, 0);
        }

        void BeginDeferredScope();
        DeferredHandles* Detach(Address* prev_limit);

        Isolate* isolate_;
        DetachableVector<Address*> blocks_;

        // Used as a stack to keep track of entered contexts.
        // If |i|th item of |entered_contexts_| is added by EnterMicrotaskContext,
        // `is_microtask_context_[i]` is 1.
        // TODO(tzik): Remove |is_microtask_context_| after the deprecated
        // v8::Isolate::GetEnteredContext() is removed.
        DetachableVector<Context> entered_contexts_;
        DetachableVector<int8_t> is_microtask_context_;

        // Used as a stack to keep track of saved contexts.
        DetachableVector<Context> saved_contexts_;
        Address* spare_;
        int call_depth_;

        Address* last_handle_before_deferred_block_;
        // This is only used for threading support.
        HandleScopeData handle_scope_data_;

        void IterateThis(RootVisitor* v);
        char* RestoreThreadHelper(char* from);
        char* ArchiveThreadHelper(char* to);

        friend class DeferredHandles;
        friend class DeferredHandleScope;
        friend class HandleScopeImplementerOffsets;

        DISALLOW_COPY_AND_ASSIGN(HandleScopeImplementer);
    };

    const int kHandleBlockSize = v8::internal::KB - 2; // fit in one page

    void HandleScopeImplementer::SaveContext(Context context)
    {
        saved_contexts_.push_back(context);
    }

    Context HandleScopeImplementer::RestoreContext()
    {
        Context last_context = saved_contexts_.back();
        saved_contexts_.pop_back();
        return last_context;
    }

    bool HandleScopeImplementer::HasSavedContexts()
    {
        return !saved_contexts_.empty();
    }

    void HandleScopeImplementer::EnterContext(Context context)
    {
        DCHECK_EQ(entered_contexts_.size(), is_microtask_context_.size());
        entered_contexts_.push_back(context);
        is_microtask_context_.push_back(0);
    }

    void HandleScopeImplementer::LeaveContext()
    {
        DCHECK(!entered_contexts_.empty());
        DCHECK_EQ(entered_contexts_.size(), is_microtask_context_.size());
        entered_contexts_.pop_back();
        is_microtask_context_.pop_back();
    }

    bool HandleScopeImplementer::LastEnteredContextWas(Context context)
    {
        return !entered_contexts_.empty() && entered_contexts_.back() == context;
    }

    void HandleScopeImplementer::EnterMicrotaskContext(Context context)
    {
        DCHECK_EQ(entered_contexts_.size(), is_microtask_context_.size());
        entered_contexts_.push_back(context);
        is_microtask_context_.push_back(1);
    }

    // If there's a spare block, use it for growing the current scope.
    internal::Address* HandleScopeImplementer::GetSpareOrNewBlock()
    {
        internal::Address* block = (spare_ != nullptr) ? spare_
                                                       : NewArray<internal::Address>(kHandleBlockSize);
        spare_ = nullptr;
        return block;
    }

    void HandleScopeImplementer::DeleteExtensions(internal::Address* prev_limit)
    {
        while (!blocks_.empty()) {
            internal::Address* block_start = blocks_.back();
            internal::Address* block_limit = block_start + kHandleBlockSize;

            // SealHandleScope may make the prev_limit to point inside the block.
            // Cast possibly-unrelated pointers to plain Addres before comparing them
            // to avoid undefined behavior.
            if (reinterpret_cast<Address>(block_start) <= reinterpret_cast<Address>(prev_limit) && reinterpret_cast<Address>(prev_limit) <= reinterpret_cast<Address>(block_limit)) {
#ifdef ENABLE_HANDLE_ZAPPING
                internal::HandleScope::ZapRange(prev_limit, block_limit);
#endif
                break;
            }

            blocks_.pop_back();
#ifdef ENABLE_HANDLE_ZAPPING
            internal::HandleScope::ZapRange(block_start, block_limit);
#endif
            if (spare_ != nullptr) {
                DeleteArray(spare_);
            }
            spare_ = block_start;
        }
        DCHECK((blocks_.empty() && prev_limit == nullptr) || (!blocks_.empty() && prev_limit != nullptr));
    }

    // Interceptor functions called from generated inline caches to notify
    // CPU profiler that external callbacks are invoked.
    void InvokeAccessorGetterCallback(
        v8::Local<v8::Name> property,
        const v8::PropertyCallbackInfo<v8::Value>& info,
        v8::AccessorNameGetterCallback getter);

    void InvokeFunctionCallback(const v8::FunctionCallbackInfo<v8::Value>& info,
        v8::FunctionCallback callback);

    class Testing {
    public:
        static v8::Testing::StressType stress_type() { return stress_type_; }
        static void set_stress_type(v8::Testing::StressType stress_type)
        {
            stress_type_ = stress_type;
        }

    private:
        static v8::Testing::StressType stress_type_;
    };

} // namespace internal
} // namespace v8

#endif // V8_API_H_
